Mario Eduardo Rangel Moreira Cavalcanti Mata

Comportamento higroscópico do extrato seco de urucum (Bixa Orellana L)

Neste trabalho, objetivou-se determinar a higroscopicidade do urucum na forma de extrato seco. Neste estudo foram obtidas as atividades de agua do extrato seco de urucum para as temperaturas de 10 a 50oC e teores de agua entre 6 e 22% base umida. A metodologia empregada para as determinacoes foi o metodo dinâmico em que se utilizou o equipamento Thermoconstanter Novasina TH-2. Para os resultados experimentais aplicaram-se as equacoes propostas por Henderson modificada por Thompson e Henderson modificada por Cavalcanti Mata e Peleg. Por meio das analises dos parâmetros encontrados concluiu-se que a equacao que melhor se ajusta aos dados experimentais e a equacao de Henderson modificada por Cavalcanti Mata e que as isotermas de adsorcao de agua do extrato de urucum seco se comportaram sigmoidalmente, sendo consideradas do tipo II.

Desidratação osmótica de fatias de jaca

The present work was undertaken with the objective of studying the kinetics and the osmotic-dehydration modeling of slices of jack-fruit in a flat layout. The osmotic treatment was carried out at 43oC, employing agitation, and using sucrose solutions at concentrations of 40o and 50o Brix. The study of the kinetics of osmotic dehydration showed that in the sucrose solution at 50o Brix, the value of the water-loss (WL) was higher after 28.5 hours of processing (68.5% wb to 40.2% wb) , slightly higher than that found for the sucrose solution at 40o Brix (68.5% wb to 43% wb). The opposite behavior was observed for the gain in solids (SG). Adjustment of the experimental data was done using the Page and Fick models. From the analysis of the Fick equation, it was found that the effective diffusivity coefficients were 0.5837 and 0.6677 mm2 min-1 for 40o and 50o Brix, respectively.

Crioconservação de sementes de algodão

The objective of this work was to evaluate the crioconservation of cotton seed. At first, the water limit content for the crioconservation (TALC) was determined. For this determination, the seeds were immerse in liquid nitrogen during five days and after this period they were unfrozen and submitted to germination and vigor test. The statistical design used was completely randomized with the factorial. A portion of seeds was used with water limit content previously determinated for the different cultivars, since this has proceeded the storage in liquid nitrogen and in nitrogen vapor. The experimental design used in this stage was completely randomized in subdivided plots over time. In each period of storage the seeds were submitted to germination and vigor tests. According to the obtained results, it was concluded that: (a) the water content limit for crioconservation (TALC), during 5 days, for the conservation of four cultivars, considering the germination of these cultivars, is between 6 and 8% and, as to the seed vigor, the TALC was 6%; (b) the seeds of the different cultivars can be crioconserved in germoplasma bank at two temperatures; (c) the crioconservation increases the percentage of germination and the vigor of the cotton seeds, due to this temperature promoting termination of dormancy by the action of cold.The objective of this work was to evaluate the crioconservation of cotton seed. At first, the water limit content for the crioconservation (TALC) was determined. For this determination, the seeds were immerse in liquid nitrogen during five days and after this period they were unfrozen and submitted to germination and vigor test. The statistical design used was completely randomized with the factorial. A portion of seeds was used with water limit content previously determinated for the different cultivars, since this has proceeded the storage in liquid nitrogen and in nitrogen vapor. The experimental design used in this stage was completely randomized in subdivided plots over time. In each period of storage the seeds were submitted to germination and vigor tests. According to the obtained results, it was concluded that: (a) the water content limit for crioconservation (TALC), during 5 days, for the conservation of four cultivars, considering the germination of these cultivars, is between 6 and 8% and, as to the seed vigor, the TALC was 6%; (b) the seeds of the different cultivars can be crioconserved in germoplasma bank at two temperatures; (c) the crioconservation increases the percentage of germination and the vigor of the cotton seeds, due to this temperature promoting termination of dormancy by the action of cold.

Comportamento reológico de méis de florada de silvestre

The rheological behavior of Apis mellifera honey produced in the State of Piaui, in the Brazilian semi-arid, obtained with predominance of Serjania glabrata flowers was studied. The samples were collected in the year 2000 by beekeepers and associations and cooperatives of beekeepers in the area covered by the municipal districts of Picos, Itainopolis, Vera Mendes and Isaias Coelho. The samples were centrifuged, filtered, decanted and the rheological measures at temperatures of 20 to 40 oC using a Brookfield Viscometer RVT model were made. The readings of rotation speed and torque were transformed in shear rate and shear stress values. The data of shear rate and shear stress were fitted by the potential Law and Herschel-Bulkley models. The samples presented pseudoplastic behavior. The potential and Herschel-Bulkley models fitted the experimental results appropriately. The increase in temperature reduced the viscosity by approximately 80%. The apparent viscosity values fitted well with an Arrhenius type equation.

Indução de superbrotamento e regeneração de plantas in vitro, nas cultivares de algodão colorido

The micropropagation in vitro has been presented as a technique that allows various methodologies which, for in turn, contribute to a reduction in the time to obtain new cultivares. The objective of this work was to evaluate the behavior of the genotypes BRS-Verde, BRS-200-Marrom, 6M-Moco-white and BRs-187-8H- white, in the induction of the multiple shoots in different combinations of growth regulators. The seeds, to obtain the initial material, were placed in a solution of 1% sodium hypochlorite of active chlorine for 20 min. The shoot had been induced, in the explant of cotiledonary nodes in MS medium basic, supplemented with 6-benzylaminopurine (BAP), Cinetina (KIN) and Tiadiazuron (TDZ), isolated or associated in different concentrations. The material was kept for 40 days in growth chamber, under controlled ambient conditions. 10 mL of medium was used for treatment with a explant for culture tube, in an entirely randomized design, with factorial arrangement of 4 x 17 (four genotypes x seventeen medium). It was observed that the MS medium supplemented with BAP (2.0 mg L-1) isolated or associated with KIN (1.0 mg L-1), promoted greater capacity of regeneration and height of sprouts; MS medium supplemented with BAP (2.5 mg L-1) stimulated greater height of sprouts and the MS medium supplemented with TDZ (1.0, 0.50 and 0.25 mg L-1) affected the capacity of regeneration of sprouts, a larger formation of calluses was observed.

Modelos de predição da cinética de secagem dos grãos de guandu

The objective of this research was to study the kinetics of the thin-layer drying of pigeon peas subjected to different drying conditions, using different mathematical models. The effective diffusivity and activation energy were determined with the Fick model. For this purpose, 200g samples of pigeon peas with an initial moisture content of 25% (w.b.) were dried in an experimental fixed bed dryer, adjusted to operate at temperatures of 40, 50, 60 and 70 °C, and a drying air rate of 1.0m s–1. For each temperature, drying was continued until the water content reached dynamic equilibrium. The average values for the temperature and relative humidity of the air were, respectively, 26 °C and 68%. For each temperature the effective diffusivity of the product was determined assuming the pigeon pea to be a sphere of equal volume. The effective diffusivity of the product in relation to the temperature was expressed by an equation similar to that proposed by Arrhenius. An analysis of the results allows for the conclusion that the equations of Cavalcanti Mata with six constants and of Midilli et al. satisfactorily represented the drying process under all conditions studied; and that using the Fick model the diffusivity of the pigeon peas ranged from 2.1x10–10 to 6.8x10–10 m2.s–1 at temperatures between 40 and 70 °C, respectively, with an activation energy equal to 34.51 kJ.mol–1.

Difusividade térmica aparente de sementes de cajá em temperaturas acima do congelamento até ultrabaixas temperaturas

The aim of this study was to determine experimentally the apparent thermal diffusivity caja seeds, evaluating the effect of variation of water content and temperature and adjust different mathematical models to experimental values. Seeds with the range of water content from 6.05 to 61.84% (wb) subjected to drying at a temperature of 40 oC were studied. The reduction of water content during drying was monitored by gravimetric method (weight loss). The apparent thermal diffusivity of caja seed was determined by the method of Dickerson. It was concluded that the apparent thermal diffusivity in temperature above freezing and ultralow temperatures as a function of water content (wb), can be satisfactorily represented by a linear regression model and that value of the apparent thermal diffusivity increases exponentially with increasing temperature.

Rheological behavior of mixed drink of annona and milk

In this study the rheological behavior in different temperatures (0; 6; 18 e 24 oC) and physicochemical parameters of integral annona (Annona squamosa) pulp and the annona pulp with milk in different percentages pulp/milk (75g of annona pulp/25g of milk, 50g of annona pulp/50g of milk, 25g of annona pulp/75g of milk) have been availed, in order to verify the effect of temperature and pulp concentration in the rheological behavior of these beverages. To obtain the rheological parameters a concentric cylinder rheometer has been used and the rheograms were analyzed using the Ostwald-de-Wael (power Law) and Herschel-Bulkley models. The physicochemical parameters (sugars, pH, ash, acidity and soluble solids) were determined in order to establish correlations with the rheological behavior. Finally, the best results had been obtained using the Herschel-Bulkley model; the low values for the behavior index (n <1) obtained confirm the pseudoplastic behavior of all samples.

Crioconservation of cotton seed

The objective of this work was to evaluate the crioconservation of cotton seed. At first, the water limit content for the crioconservation (TALC) was determined. For this determination, the seeds were immerse in liquid nitrogen during five days and after this period they were unfrozen and submitted to germination and vigor test. The statistical design used was completely randomized with the factorial. A portion of seeds was used with water limit content previously determinated for the different cultivars, since this has proceeded the storage in liquid nitrogen and in nitrogen vapor. The experimental design used in this stage was completely randomized in subdivided plots over time. In each period of storage the seeds were submitted to germination and vigor tests. According to the obtained results, it was concluded that: (a) the water content limit for crioconservation (TALC), during 5 days, for the conservation of four cultivars, considering the germination of these cultivars, is between 6 and 8% and, as to the seed vigor, the TALC was 6%; (b) the seeds of the different cultivars can be crioconserved in germoplasma bank at two temperatures; (c) the crioconservation increases the percentage of germination and the vigor of the cotton seeds, due to this temperature promoting termination of dormancy by the action of cold.The objective of this work was to evaluate the crioconservation of cotton seed. At first, the water limit content for the crioconservation (TALC) was determined. For this determination, the seeds were immerse in liquid nitrogen during five days and after this period they were unfrozen and submitted to germination and vigor test. The statistical design used was completely randomized with the factorial. A portion of seeds was used with water limit content previously determinated for the different cultivars, since this has proceeded the storage in liquid nitrogen and in nitrogen vapor. The experimental design used in this stage was completely randomized in subdivided plots over time. In each period of storage the seeds were submitted to germination and vigor tests. According to the obtained results, it was concluded that: (a) the water content limit for crioconservation (TALC), during 5 days, for the conservation of four cultivars, considering the germination of these cultivars, is between 6 and 8% and, as to the seed vigor, the TALC was 6%; (b) the seeds of the different cultivars can be crioconserved in germoplasma bank at two temperatures; (c) the crioconservation increases the percentage of germination and the vigor of the cotton seeds, due to this temperature promoting termination of dormancy by the action of cold.

DETERMINING THE DIFUSION CO-EFFICIENT OF RIPE AND SEMI-RIPE UMBU FRUITS (Spondias tuberosa, Arruda Câmara) DURING THE THIN DRYING LAYER

The present work has got as its aim to determine the co-efficient of umbu fruits diffusion whilst semi-ripe and ripe obtained from the thin drying curves made at temperature levels of 70, 80 and 90oC. The drying processes have been made in a experimental dryer with an initial moisture level of 81,52, and 83,18% wet basis, for semi-ripe and ripe umbu, respectively up to the final water rates of 40, 35, and 30%b.u.. The drying air speed was 1,27m.s -1 . In order to obtain the diffusion co-efficient, Fick’s equation was used for one sphere, one two and three terms of the series being used with a help of the non-linear regression program (Statistica version 5.0). Due to the obtained results, we could come into a conclusion that the diffusion co-efficient of Fick’s equation for ripe and semi-ripe umbu fruits increases along with the drying temperature, and whenever dada is placed according to temperature, they can be expressed by an Arrhenius-like equation.